Sensors aid in nitrogen application to corn

The Agricultural Research Service along with University of Missouri researchers have been working on using sensors to measure the light reflected from corn as it is growing in the field to determine the amount of nitrogen to apply since 2004. This research is focused on applying nitrogen only where it is needed in the field. The corn plant’s early season color is the best indicator of nitrogen needs.

There are a number of sensors that are commercially available for use in crop production. The two most popular brands are NTech’s GreenSeeker which uses a red sensor and Holland Scientifics’ Crop Circle which is an amber sensor. Each of these instruments uses their own light energy.

These devices can be mounted to a tractor or applicator and then as the equipment passes through the field, the sensors measure on the go and this information is used to change application rates of nitrogen products.

The University of Missouri and Ag Research Service of USDA have worked together to develop algorithm which is used to interpret the sensed data and use this information to determine the amount of nitrogen that should be applied to the growing crop. The calculated fertilizer rate is sent to the variable rate controller and then the recommended nitrogen rate is applied to the growing crop. This process is repeated every second which allows the grower to apply the precise amount of nitrogen as required by the crop.

For more information, contact Wayne Flanary at 660-446-3724 or Heather Benedict at 660-425-6434, Regional Agronomists, University of Missouri Extension.